Method of treating petroleum oils



Mardi 24, 1931. Q B, WATSN 1,797,305

METHOD OE- TREATING PETROLEUM OILS Filed Aug. 2l. 192B aucun Patented Mar. 24, 1931 UNITEDl STATES PATE NT clarion;A

COBINIILLIUS B. AWATSON, OF CHICAGO, ILLINOIS, ASSIGNOB T0 GYRO PROCESS COM- PANY, F DETROIT, MICHIGAN, A. CORPORATION OF MICHIGAN METHOD 0F TREATING PETROLEUM OILS lApplication iiledy August 21, 1928. Serial No'. 300,997.

This invention relates to an improved method of treating hydrocarbon oils such vas crude oils or other oils containing fractions of widely differing boiling range, and has for its primary object the provision of an efficient system of heat treating such oils for the purpose of obtaining fractional separation thereof, and in certain instances the vapor phase conversion of one or more ofthe higher boiling fractions so separated into fractions or compounds of lower boiling range. i

'It is another object of the invention to provide an oil treating system wherein the oils charged thereto may be in the form of crude oil containing appreciable quantities of free or natural gasoline and wherein an improved methodl of heat interchange is provided for the purpose of separately removing -fr'om the system the free gasoline or other natural low boiling point compounds from the charging stock prior to the circulation of the main body of oil through the principal heating and converting zone of the system. It has been observed that free or natural gasoline obtained from paraiiin base hydrocarbon oils is often lnot as desirable as a fuel for internal combustion engines as the socalled cracked or synthetic fuels, Aespecially such fuels as are produced byhiah temperature or vapor phase cracking.` This is due to the fact that natural gasoline of the character specified has a decided tendency to knock or detonate when exploded in the cvlinders of an engine, whereas the cracked fuel is substantially non-detonating. Heretofore in charging crudes to cracking equipment, it has been the custom to allow the vapors of natural gasoline to intermingle with the vapors produced by the cracking operations` with the.

result that a blended fuel, containing both the natural gasoline and the cracked gasolines is produced and the blending results in a fuel of lower anti-knock value. Therefore,l the present invention provides a system for charging crude to a vapor phase crack-ing still y and the securing a sufficient heat interchange and in accomplishing this operation in such a manner that the vaporized natural gasoline iss-'separately discharged from theI systemwith respect to the vapor-ized cracked gasolines.

It is another object ofthe invention to provide a heat exchanging system which receives lits heating medium from the oil vapors discharged from the converting unit of the system, and to situate within said heat exchanger a coil or the equivalent thereof through which the fresh charging stock is circulated, in order that the heat contained in the vapors diso charged from the converter may be transferred through said coil and absorbed by the charging stock circulating therethrough, whereby the temperature of the latter may be elevated sufficiently to distill 0H the free gasoline content therein present.

It is another ob'ect of the invention to use the higher boiling compounds of the charg# -ingstock, after the removal of the low boilrneral 1 designates a converter or other type of heating apparatus through which oil is circulated and heated to a temperature suHicient to effect conversion and to reduce the oil to a dry vaporous state. Leading fromv the outlet side of the converter l is a pipe line 2 which extends into the casing of a heat exchanger 3. l

Arranged within this heat exchanger is al closed coil 4, the inlet side' of which is connected with a pipe line 5 which leads from a supply tank 6 o r other storage point for the charging s'tockand which is preferably crude oil containing normal quantities of free gasoline. The pipev line f5 ,ispreferably provided with a pump 7- to ei'ect' the forced passage of the oil from the tank through l'the line 5 and thence through the coil 4 situthe heated oil vapors, released from the convThe nozzle 15 verter, to permit of the vaporization of the gasoline fraction of the original charging stock. This gasoline fraction passes overhead by way of the line 10 to a condenser 11 and is then transferred to a free gasoline storage tank 12.

The unvaporized oil which collects in the bottom of the separator has boiling points materially higherthan those of the free gasoline or other low boiling point materials. This relatively heavy oil in liquid form is then forced by way of a pipe line 13 and al pump 14 through a nozzle 15 lsituated within the casing of the heat exchanger 3. is so disposed within the heat exchanger that the oil released therefrom is brought into intimate contact with the highly heated cracked oil vapors discharged from the converter 1. For example, the vapors discharged from the con-' verter 1 flow through 'the line 2 and into the heat exchanger 3 at a temperature of ap- 'proximately 1100 degrees F. This temperature is substantially instantaneously lowered by contact with the relatively colder oil discharged from the nozzle 15. The temperature of the oil forced through the line 13 at or near the nozzle may be approximately 300 degrees F., and due to this relatively low temperature it will be seen that the temperature of the oil vapors of the converter will be practically immediately lowered to a temperature not in excess of 600 degrees F., thus preventing further cracking reactions taking place in the `converted vapors. These temperatures are suflicient to heat the coil 4 to secure the topping of the charging stock forced through said coil.

The vapors remaining in the heat exchanger pass overhead by way of a line 16 to suitable fractionating and purifying apparatus 16a which permit a final motor fuel product to be obtained. lThe liquid unvaporized oil in the bottom of the heat exchanger is discharged by way of a pipe line '17 and is circulated or recirculated through the converter 1.

In view of the foregoing it will be seen that the present invention provides a simple yet effective method of heat interchange which is both effective in operation as well kas economical. The system permits the crude charging stock to be readily deprived of its free gasoline content and to permit the remaining fractions to be employed as a chargson of sharp cooling of the oil vapors re-l leased from the converter and the practically instantaneous arresting of the conversion reactions, little or no deposit of free carbon in the system takes place.

The liquid condensate which accumulates in the bottom of the fractionating tower 16% is forced by way of the pipe line 17 and the hot oil pumpy 18 through a preheater or economizer 19, where the liquid oil is vaporized and passes by way of a line 20 into an evaporator 21. The stock which is not vaporized at the temperatures prevailing in the evaporator, which may be, for example, 650 F., accumulates as a liquid in the bottom of the evaporator and is permanently removed from the system by way of the line 22 as fuel oil. The vapors pass 'overhead from the evaporator and enter the converter by way of the pipe line 23. In the converter the temperature of the vapors is rapidly raised to conversion temperatures preferably in excess of 1000 F. and are delivered to the heat exchanger as previously described wherein the operation above given is repeated. The preheater 19 may receive its sources of heat from the outlet gases of the converter. An excess oil container 24 may be connected with the bottom of the fractionating tower 1ba for the purpose of regulating the quantity of material introduced into the system.A From the fractionating tower 16a the vapors are suitablydischarged and condensed and may be purified by any suitable method, such as treatment with fullers earth or the ordinary being suitable for use as a motor fuel and l possesses a high anti-knock value.

The provision of the closed coil 4 inthe heat exchanger 3 provides for the separate withdrawal from the system of the so-called straight-run gasoline fractions of the charging stock andthe cracked distillate produced by. the operation of the conversion zone. This is of considerable importance in that the straight-run gasoline and cracked distillate possess markedly different characteristics, especially in the matter of relative anti-knock values. The cracked distillate is usually greatly superior to the'straight-run product -in this respect and therefore the present invention provides for the separate withdrawal from the system of the straightrun and cracked distillates.

What is claimed is: f

1. The method of treating petroleum which comprises' subjecting petroleum from which free gasoline has been removed to heat in a still to vaporize the petroleum, conducting the vapor toa cracking apparatus and there subjecting the vapor to a temperature suicient charging stock containing free gasoline.

through a closed coil arranged within said receptacle, whereby such charging stock is heated suiiciently to effect the vaporization of the low boiling point compounds thereof, in separately removing said vaporized low boiling point compounds from the charging stock, and in separately discharging the higherboiling point compounds ofthe charging stock into the receptacle in liquid form for admixture with the vapors -discharged from said cracking apparatus, to lower the temperature ofy saidcracked vapors and to abruptly arrest further cracking reactions therein.

2. In the manufacture of low boiling petroleum oils from high boiling petroleum oils, the process which consists in subjecting topped petroleum oils from which free gasoline has been removed to temperatures in excess of 10000 F. to vaporize such oils and convert the high boiling point fractions thereof into fractions having relatively low boiling points, in discharging the cracked vaporized fractions at the temperature specified into a separate receptacle, 'in passing a charging stock containing free gasoline to a heat exchanger arranged in said receptacle to heat such charging stock by indirect heat exchange with said vapors so that the temperature of the charging stock will be elevated sufficiently to vaporize and liberate the free gasoline contained therein from the remaining liquid oils of higher boiling range, in separately removing the vaporized free gasoline from said higher boiling oils, and in then.

returning the latter to said receptacle for direct and intimate -contact with the cracked vapors introduced into the receptacle.

3. A method of treating petroleum which comprises subjecting the vaporv of a petroleum from which free gasoline has been removed to temperatures sufficient to' break down the high boiling point com ounds into compounds having relatively ow boiling points, in passing such crackedvapors into a separate receptacle, in passing a liquid charging stock through said receptacle in indirect heat exchange with the cracked heatedvvapors within the receptacle, whereby said charging stock is heated suiiiciently to vaporize and liberate the free gasoline contained therein, separately Yremoving the free gasoline from the charging stock, and in returning the remaining body of the charging stock to the interior of said receptacle so that said body will be brought into direct contact with the cracked vapors entering said receptacle.

which free gasoline has been removed to heat in a still to vaporize the petroleum;'second, conducting the vapor to a cracking apparatus and there subjecting the vapor to a tempera'- ture in excess of 1000o F. to break down the high boiling point compounds into compounds having relatively low boiling points; third, conducting the highly heated cracked vapor from the cracking apparatus yto a separate receptacle wherein said vapors are cooled to a noncracking temperature below substantially 600 F; fourth, in passing a charging stock containing freegasoline through a coil contained in said receptacle for the purpose of heating said charging stock suiciently to vaporize the Aunvaporized free gasoline contained thereinby indirect heat eX- change with said cracked vapors; fifth, separately removing the freeV gasoline from the charging stock and separately collecting the same; and, sixth, returning the remaining body of the charging stock to said receptacle for direct -and intimate admixture with thel cracked vapors discharged into said receptacle so that the relatively cooler charging stock will effect an abrupt reduction in the temperature of the cracked vapors. n

5. A method of treating petroleum which comprises, first, subjecting petroleum from which free gasoline has been removed to heat in a still to vaporize the petroleum; second, conducting the vapor to a cracking apparatus and th ere subjecting the vapor to a temperature in excess of 1000o F. to break down the high boiling point compounds into compounds having relatively low boiling points; third, conducting the highly heated cracked vapor from the cracking apparatus to a separate' receptacle wherein said vapors are cooled to a noncracking temperature below substantially 600 F.; fourth, in circulating a chargingsto'ck containing free gasoline through a coil contained in lsaid receptacle for the purpose of heating said charging stock suiiiciently to vaporize the free gasoline contained therein by indirect heat exchange with said cracked vapors; fifth, separately removing the thusvaporized free gasoline from the charging stock and collecting the same; sixth, returning the remaining liquid body of the charging stock to said receptacle for direct and intimate admixture with the.

cracked vapors discharged `into said receptacle so'that the relatively cooler charging stock will effect an abrupt reduction in' the temperature of the cracked vapors; seventh, separately removing the vapors from the recep.

tacle; and, eighth, removin the unvaporized oil from said receptacle an passing the same through the cracking zone of the system.

In testimony whereof I aiixm signature.

CORNELIUS B. ATSON.

4; A method of treating petroleum which I comprises, first, subjecting petroleum from 

